The identification of vulnerability characteristics and assessing the performance of existing structures with regard to earthquakes are essential steps in reducing the losses and enhancing the resilience of societies and cities. In the past, most of the initial work on structural assessment was based only on the visual inspection of buildings, NDT methods, and engineering judgement. The last decade, however, has seen a growth in the technological development of various tools that are able to greatly support the prediction of structural safety. The mentioned topics are greatly expressed in pre- and post- earthquake assessments, reconstructions, and renovations of buildings and cities. Case studies of real examples represent a bridge between practice and research. They provide a method for research in which the complexity of the process and outcome of the results contribute to a valuable database for all techniques in preserving the existing building stock. This Collection aims to compile original and high-quality papers and case studies that address the assessment, monitoring, reconstruction, maintenance, and preservation of existing structures.